Reversible brush-holder for use with dynamos.



L. CREVELING. REVERSIBLE BRUSH HOLDERIFOR USE WITH DYNAMOS.

APPLICATION FILED AUGJI 1911.

1,253, 157. Patented Jan. 8,1918.

WITNESSES M/VE/I/TUI? W ED S AT 'PAT NT QFFICE: 1

JOHNTL. cnnvnnine, or New YonK, N. I, ns'sieivon "'r'o SAFETY can EAT nGANb LIGHTING COMPANY, a oonrona rron on nEw'JEnsEY. y

f REVERSIBLE BRUSH-HOLDER FOR USE WITH DYNAMOS.

.To all whom it may]. concern:

Be it known that I, JOHN L. CREVELING, a resident of New York, in the county and Stateof New York, have invented certain new and useful Improvements in Reversible Brush-l-Iolders for Use with=Dynam0s, .as set forth in the annexed-specification and drawing forming a partthereof.

My invention pertains to that class of dynamos wherein itis desired to maintain the current of uniform polarity regardless of reversals in direction of rotation of the armature, and has for itsparticular Ob ectto provide means for satisfactorily. compensating for reversals in rotation of the armature. "The drawing is a partial sectioniand ele- 'vation. of a portion of a dynamoicompre bending my invention. H

In the drawing, 1 represents the usual armature of a dynamo provided withthe commutator 2, the said armature being carried by the usual shaft (not shown) running in the usual type of bearing carried within the bearingunember, orcasting, 8

which is preferably provided with a 'flanged portion 1 adapted to be held firmly against the end of the field frame indicated at 5 as by screws 6. The bearing member or end casting also carries a cylindrical extension 7 provided with a ball-race or channel indicated at 8 into which are free to travel the balls 9 engaging a corresponding ballrace in an annular ring 10 which is provided with arms 11 carrying suitable brushholders as indicated at 12 which are pro vided with brushes as indicated at 13. As the ball bearing for the ring 10 will allow the said ring to rotate with very little friction, the drag or friction of the brushes 13 upon the commutator 2 will rotate the ring 10 in one direction or the other depending upon the direction of rotation of the armature unless stopped by some engaging means. For this purpose I provide a stop 14 which will allow the ring 10 and brushes 13 to revolve through substantially one hundred and eighty degrees when a bi-polar machine, as indicated in the drawing, is used. This revolution of the brushes in one direction or the other will shift the brushes from one end of the axis of commutation 'to the other and, therefore, cause the brush which is the positive brush when the generator is running in one direction to occupy the position of the negative brush when running in Specification of Iletters Patent.

.result outlined above.

1 in the member I -,net awayfrom the ring 10 and the face of the member 7,.thebrackets 16 being so 'addicated in the drawing.

' the other direction, and thus compensate for changes in direction of the armature current it will be obviousthat a machine with any proper number. of poles may be used and the are through which the brushes are shifted determined accordingly to accomplish the p In order to more securely holdsthe ring 10in its .proper position when the-generator is in operation and toprevent chattering of the brushes from ftending in time to wear; or pit the:ball-races,

I provide an: annularwelectromagnet, the field frame of which 18 indicated at .15 and which may be carried as upon brackets of brass, or other-nonmagnetic material, in-

dicated -at.16. A series of small spiral springs 17 are preferably let ain'to' recesses and tend to press theanagjusted that the air gap between the magnet frame 15 and the members '10 and 7 isvery smallalways. The magnet is provided with the winding 18 dependent for excitation upon the armature 1 as, for example, placed in shunt across the generator brushes as in- 19 represents one of a series ofslip pins which may be used if desired to keep the magnet frame 15 from revolving upon its brackets or support.

The operation of my dynamo is substantially as follows:

If the armature 1 and commutator 2 be revolving in such direction that the top portion of the armature is moving toward the observer, then the friction of the brushes will cause the arm 11 to revolve the member 10 until arrested by the stop 14L and the parts will be in the positions shown in the drawing. If now the generator speed increase until its voltage be appreciable, the winding 18 will become energized and the magnet frame 15 will be drawn into contact with the face of the member 7 and the ring 10, to which members it is preferably smoothly fitted. As this will form an exceptionally good magnetic circuit the tractive effect of the electromagnet will be considerable, and the ring 10 will be rigidly held in its proper position and practically no strain will be borne by the balls 9 and ball-race 8. The ring 10 will be firmly held by the magnet 1518 so long as the generator elec- V H P wneaJ I-S 19 8- Ap'plieation'filedAugustY,1911; Seria 1No.642,582. r

be free to revolve into the reverse position. If the generator armature now "be revolved in a reverse direction the revolving of the brushes will maintain the current of proper polarity to line and the magnet 18 will again become energized and grasp the members 7 and 10 and hold the ring 10 firmly in place and relieve the balls and ball-races of strain as above outlined.

From the foregoing it Wlll be obvious that my dynamo is provided with a pole changing apparatus and electromagnetic means for carrying the mechanical strain usually borne by the pole changer bearing when the generator is running and that when the generator is still and incondition for reversal the pole changing apparatus will be released and capable of proper action. upon said reversal. A

I do not wish in anyway to limit myself to any details of construction or exact mode of operation set forth in this specification, which are given toillustrate one type of generator embodying the essentials of my invention, for it will beobvious to those skilled in the art. that wide departure in the way of details may be made without departing from the spirit and scope of my invention which is as set forth .in the following claims:

14A dynamo electric machine having an armature and a commutator; together with a plurality of commutator brushes, 1 and brush-holding devices adapted to be moved by friction. of the brushes with the commutator in either direction through definite arcs; means for pivotally connecting the brush-holding devices with a stationary part of the machine, and stationary means con.- nected with a stationary part of the machine for limiting the movement of said brush- 7 the armature.

- JOHN L." onnvntine Witnesses: i v

I ANNA MARIE VALE, I

Hnnsnovrrz;

Copies of this patent maybe obtained for five cents each, by addressing the Gommlssloner of Patents,

, Washington, D. G. a Y I 

